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(append_file): Open the file before statting it, to avoid a race.

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Complain about file shrinkage only when we reach EOF.
This commit is contained in:
Paul Eggert
1999-07-12 13:03:58 +00:00
parent 9c540db933
commit 4dd9bd50bd
1 changed files with 32 additions and 33 deletions
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65
src/update.c
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@@ -45,52 +45,51 @@ char *output_start;
static void
append_file (char *path)
{
int handle;
int handle = open (path, O_RDONLY | O_BINARY);
struct stat stat_data;
off_t bytes_left;
if (stat (path, &stat_data) != 0
|| (handle = open (path, O_RDONLY | O_BINARY), handle < 0))
if (handle < 0)
{
ERROR ((0, errno, _("Cannot open file %s"), path));
return;
}
bytes_left = stat_data.st_size;
while (bytes_left > 0)
if (fstat (handle, &stat_data) != 0)
ERROR ((0, errno, "%s", path));
else
{
union block *start = find_next_block ();
size_t buffer_size = available_space_after (start);
ssize_t status;
off_t bytes_left = stat_data.st_size;
if (bytes_left < buffer_size)
{
buffer_size = bytes_left;
status = buffer_size % BLOCKSIZE;
if (status)
memset (start->buffer + bytes_left, 0,
(size_t) (BLOCKSIZE - status));
}
status = safe_read (handle, start->buffer, buffer_size);
if (status < 0)
while (bytes_left > 0)
{
union block *start = find_next_block ();
size_t buffer_size = available_space_after (start);
ssize_t status;
char buf[UINTMAX_STRSIZE_BOUND];
FATAL_ERROR ((0, errno,
_("Read error at byte %s reading %lu bytes in file %s"),
STRINGIFY_BIGINT (stat_data.st_size - bytes_left, buf),
(unsigned long) buffer_size, path));
}
bytes_left -= status;
set_next_block_after (start + (status - 1) / BLOCKSIZE);
if (bytes_left < buffer_size)
{
buffer_size = bytes_left;
status = buffer_size % BLOCKSIZE;
if (status)
memset (start->buffer + bytes_left, 0,
(size_t) (BLOCKSIZE - status));
}
if (status != buffer_size)
{
char buf[UINTMAX_STRSIZE_BOUND];
FATAL_ERROR ((0, 0, _("%s: File shrunk by %s bytes, (yark!)"),
path, STRINGIFY_BIGINT (bytes_left, buf)));
status = safe_read (handle, start->buffer, buffer_size);
if (status < 0)
FATAL_ERROR ((0, errno,
_("Read error at byte %s reading %lu bytes in file %s"),
STRINGIFY_BIGINT (stat_data.st_size - bytes_left,
buf),
(unsigned long) buffer_size, path));
if (status == 0)
FATAL_ERROR ((0, 0, _("%s: File shrunk by %s bytes, (yark!)"),
path, STRINGIFY_BIGINT (bytes_left, buf)));
bytes_left -= status;
set_next_block_after (start + (status - 1) / BLOCKSIZE);
}
}